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  Subjects -> ENGINEERING (Total: 2244 journals)
    - CHEMICAL ENGINEERING (187 journals)
    - CIVIL ENGINEERING (179 journals)
    - ELECTRICAL ENGINEERING (97 journals)
    - ENGINEERING (1205 journals)
    - ENGINEERING MECHANICS AND MATERIALS (375 journals)
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    - INDUSTRIAL ENGINEERING (61 journals)
    - MECHANICAL ENGINEERING (87 journals)

CHEMICAL ENGINEERING (187 journals)                     

Showing 1 - 0 of 0 Journals sorted alphabetically
AATCC Journal of Research     Full-text available via subscription   (Followers: 3)
ACS Sustainable Chemistry & Engineering     Hybrid Journal  
Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials     Hybrid Journal   (Followers: 4)
Acta Polymerica     Hybrid Journal   (Followers: 7)
Additives for Polymers     Full-text available via subscription   (Followers: 20)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 5)
Advanced Chemical Engineering Research     Open Access   (Followers: 12)
Advanced Powder Technology     Hybrid Journal   (Followers: 12)
Advances in Applied Ceramics     Hybrid Journal   (Followers: 4)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 21)
Advances in Chemical Engineering and Science     Open Access   (Followers: 33)
Advances in Polymer Technology     Hybrid Journal   (Followers: 12)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 5)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 8)
Anti-Corrosion Methods and Materials     Hybrid Journal   (Followers: 5)
Applied Petrochemical Research     Open Access   (Followers: 2)
Asia-Pacific Journal of Chemical Engineering     Hybrid Journal   (Followers: 7)
Biochemical Engineering Journal     Hybrid Journal   (Followers: 12)
Biofuel Research Journal     Open Access   (Followers: 3)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 9)
Brazilian Journal of Chemical Engineering     Open Access   (Followers: 3)
Bulletin of Chemical Reaction Engineering & Catalysis     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 3)
Carbohydrate Polymers     Hybrid Journal   (Followers: 7)
Catalysts     Open Access   (Followers: 5)
ChemBioEng Reviews     Full-text available via subscription  
Chemical and Engineering News     Free   (Followers: 10)
Chemical and Materials Engineering     Open Access   (Followers: 3)
Chemical and Petroleum Engineering     Hybrid Journal   (Followers: 9)
Chemical and Process Engineering     Open Access   (Followers: 5)
Chemical and Process Engineering Research     Open Access   (Followers: 7)
Chemical Communications     Full-text available via subscription   (Followers: 62)
Chemical Engineering & Technology     Hybrid Journal   (Followers: 30)
Chemical Engineering and Processing: Process Intensification     Hybrid Journal   (Followers: 14)
Chemical Engineering and Science     Open Access   (Followers: 5)
Chemical Engineering Communications     Hybrid Journal   (Followers: 11)
Chemical Engineering Journal     Hybrid Journal   (Followers: 21)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 20)
Chemical Engineering Research Bulletin     Open Access   (Followers: 2)
Chemical Engineering Science     Hybrid Journal   (Followers: 19)
Chemical Geology     Hybrid Journal   (Followers: 13)
Chemical Papers     Hybrid Journal   (Followers: 2)
Chemical Product and Process Modeling     Hybrid Journal   (Followers: 3)
Chemical Reviews     Full-text available via subscription   (Followers: 127)
Chemical Society Reviews     Full-text available via subscription   (Followers: 38)
Chemical Technology     Open Access   (Followers: 5)
ChemInform     Hybrid Journal   (Followers: 4)
Chemistry & Industry     Hybrid Journal   (Followers: 2)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry of Materials     Full-text available via subscription   (Followers: 134)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 6)
Chinese Chemical Letters     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Engineering     Full-text available via subscription   (Followers: 3)
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 1)
Coke and Chemistry     Hybrid Journal   (Followers: 1)
Coloration Technology     Hybrid Journal  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 10)
Computer Aided Chemical Engineering     Full-text available via subscription   (Followers: 1)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
CORROSION     Full-text available via subscription   (Followers: 19)
Corrosion Engineering, Science and Technology     Hybrid Journal   (Followers: 35)
Corrosion Reviews     Hybrid Journal   (Followers: 3)
Crystal Research and Technology     Hybrid Journal   (Followers: 5)
Current Opinion in Chemical Engineering     Open Access   (Followers: 4)
Education for Chemical Engineers     Hybrid Journal   (Followers: 4)
Eksergi     Open Access  
Emerging Trends in Chemical Engineering     Full-text available via subscription  
European Polymer Journal     Hybrid Journal   (Followers: 40)
Fibers and Polymers     Full-text available via subscription   (Followers: 3)
Fluorescent Materials     Open Access   (Followers: 1)
Focusing on Modern Food Industry     Open Access   (Followers: 2)
Frontiers of Chemical Science and Engineering     Hybrid Journal   (Followers: 1)
Gels     Open Access  
Geochemistry International     Hybrid Journal   (Followers: 2)
Handbook of Powder Technology     Full-text available via subscription   (Followers: 3)
Heat Exchangers     Open Access   (Followers: 1)
High Performance Polymers     Hybrid Journal  
Hungarian Journal of Industry and Chemistry     Open Access  
Indian Chemical Engineer     Hybrid Journal   (Followers: 4)
Indian Journal of Chemical Technology (IJCT)     Open Access   (Followers: 9)
Industrial & Engineering Chemistry     Full-text available via subscription   (Followers: 9)
Industrial & Engineering Chemistry Research     Full-text available via subscription   (Followers: 20)
Industrial Chemistry Library     Full-text available via subscription   (Followers: 3)
Info Chimie Magazine     Full-text available via subscription   (Followers: 3)
International Journal of Chemical and Petroleum Sciences     Open Access   (Followers: 2)
International Journal of Chemical Engineering     Open Access   (Followers: 6)
International Journal of Chemical Reactor Engineering     Hybrid Journal   (Followers: 2)
International Journal of Chemical Technology     Open Access   (Followers: 5)
International Journal of Chemoinformatics and Chemical Engineering     Full-text available via subscription   (Followers: 2)
International Journal of Food Science     Open Access   (Followers: 2)
International Journal of Industrial Chemistry     Open Access  
International Journal of Polymeric Materials     Hybrid Journal   (Followers: 5)
International Journal of Science and Engineering     Open Access   (Followers: 4)
International Journal of Waste Resources     Open Access   (Followers: 3)
Journal of Chemical Engineering & Process Technology     Open Access   (Followers: 4)
Journal of Applied Crystallography     Hybrid Journal   (Followers: 5)
Journal of Applied Electrochemistry     Hybrid Journal   (Followers: 10)
Journal of Applied Polymer Science     Hybrid Journal   (Followers: 100)
Journal of Biomaterials Science, Polymer Edition     Hybrid Journal   (Followers: 9)
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Chemical & Engineering Data     Full-text available via subscription   (Followers: 10)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Ecology     Hybrid Journal   (Followers: 5)
Journal of Chemical Engineering     Open Access   (Followers: 6)
Journal of Chemical Engineering and Materials Science     Open Access   (Followers: 1)
Journal of Chemical Science and Technology     Open Access   (Followers: 4)
Journal of Chemical Sciences     Partially Free   (Followers: 17)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Chemical Theory and Computation     Full-text available via subscription   (Followers: 13)
Journal of CO2 Utilization     Hybrid Journal   (Followers: 1)
Journal of Coatings     Open Access   (Followers: 4)
Journal of Crystallization Process and Technology     Open Access   (Followers: 6)
Journal of Environmental Chemical Engineering     Hybrid Journal   (Followers: 3)
Journal of Food Measurement and Characterization     Hybrid Journal  
Journal of Food Processing & Technology     Open Access  
Journal of Fuel Chemistry and Technology     Full-text available via subscription   (Followers: 4)
Journal of Fuels     Open Access  
Journal of Geochemical Exploration     Hybrid Journal  
Journal of Industrial and Engineering Chemistry     Hybrid Journal   (Followers: 1)
Journal of Information Display     Hybrid Journal  
Journal of Inorganic and Organometallic Polymers and Materials     Partially Free   (Followers: 6)
Journal of Modern Chemistry & Chemical Technology     Full-text available via subscription   (Followers: 2)
Journal of Molecular Catalysis A: Chemical     Hybrid Journal   (Followers: 5)
Journal of Non-Crystalline Solids     Hybrid Journal   (Followers: 7)
Journal of Ocean University of China (English Edition)     Hybrid Journal  
Journal of Organic Semiconductors     Open Access   (Followers: 4)
Journal of Physics and Chemistry of Solids     Hybrid Journal   (Followers: 5)
Journal of Polymer and Biopolymer Physics Chemistry     Open Access   (Followers: 4)
Journal of Polymer Engineering     Hybrid Journal   (Followers: 8)
Journal of Polymer Research     Hybrid Journal   (Followers: 6)
Journal of Polymer Science Part C : Polymer Letters     Hybrid Journal   (Followers: 5)
Journal of Polymers     Open Access   (Followers: 2)
Journal of Polymers and the Environment     Hybrid Journal   (Followers: 1)
Journal of Powder Technology     Open Access   (Followers: 1)
Journal of Pure and Applied Chemistry Research     Open Access   (Followers: 1)
Journal of the American Chemical Society     Full-text available via subscription   (Followers: 222)
Journal of the Bangladesh Chemical Society     Open Access  
Journal of the Brazilian Chemical Society     Open Access   (Followers: 2)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 1)
Journal of the Pakistan Institute of Chemical Engineers     Open Access   (Followers: 1)
Journal of the Taiwan Institute of Chemical Engineers     Hybrid Journal   (Followers: 2)
Journal of Water Chemistry and Technology     Hybrid Journal   (Followers: 7)
Jurnal Inovasi Pendidikan Kimia     Open Access  
Jurnal Reaktor     Open Access  
Jurnal Teknologi Dan Industri Pangan     Open Access   (Followers: 1)
Korean Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
Main Group Metal Chemistry     Hybrid Journal   (Followers: 1)
Materials Chemistry and Physics     Full-text available via subscription   (Followers: 14)
Materials Sciences and Applied Chemistry     Full-text available via subscription  
Molecular Imprinting     Open Access  
MRS Communications     Hybrid Journal  
Nanocontainers     Open Access  
Nanofabrication     Open Access  
Noise Control Engineering Journal     Full-text available via subscription   (Followers: 2)
Ochrona Srodowiska i Zasobów Naturalnych : Environmental Protection and Natural Resources     Open Access  
Petroleum Chemistry     Hybrid Journal   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription   (Followers: 3)
Plasma Processes and Polymers     Hybrid Journal  
Plasmas and Polymers     Hybrid Journal  
Polymer     Hybrid Journal   (Followers: 84)
Polymer Bulletin     Hybrid Journal   (Followers: 7)
Polymer Composites     Hybrid Journal   (Followers: 13)
Powder Technology     Hybrid Journal   (Followers: 12)
Recyclable Catalysis     Open Access   (Followers: 1)
Research on Chemical Intermediates     Hybrid Journal  
Reviews in Chemical Engineering     Hybrid Journal   (Followers: 5)
Revista ION     Open Access  
Revista Mexicana de Ingeniería Química     Open Access  
Rubber Chemistry and Technology     Full-text available via subscription   (Followers: 2)
Russian Chemical Bulletin     Hybrid Journal   (Followers: 2)
Russian Journal of Applied Chemistry     Hybrid Journal   (Followers: 1)
Science and Engineering of Composite Materials     Hybrid Journal   (Followers: 54)
Solid Fuel Chemistry     Hybrid Journal  
South African Journal of Chemical Engineering     Open Access   (Followers: 2)
South African Journal of Chemistry     Full-text available via subscription   (Followers: 2)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 5)
Sustainable Chemical Processes     Open Access   (Followers: 1)
Synthesis Lectures on Chemical Engineering and Biochemical Engineering     Full-text available via subscription  
The Canadian Journal of Chemical Engineering     Hybrid Journal   (Followers: 3)
The Chemical Record     Hybrid Journal   (Followers: 1)
Theoretical Foundations of Chemical Engineering     Hybrid Journal   (Followers: 2)
Transition Metal Chemistry     Hybrid Journal   (Followers: 2)
Transylvanian Review of Systematical and Ecological Research     Open Access  
Visegrad Journal on Bioeconomy and Sustainable Development     Open Access   (Followers: 1)
Zeitschrift für Naturforschung B : A Journal of Chemical Sciences     Open Access   (Followers: 1)

           

Journal Cover Chemical Engineering Science
  [SJR: 1.178]   [H-I: 114]   [19 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0009-2509
   Published by Elsevier Homepage  [2970 journals]
  • A theoretical study on drop breakup modeling in turbulent flows: The
           inertial subrange versus the entire spectrum of isotropic turbulence
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Jannike Solsvik, Vidar T. Skjervold, Luchang Han, He'an Luo, Hugo A. Jakobsen
      The traditional model framework for drop breakup in turbulent flows is based on the inertial subrange of turbulence. That is, Kolmogorov's formulas for the energy spectrum and second-order longitudinal structure function are used. In recent literature the model framework has been extended to consider the wide energy spectrum (i.e. including the dissipation, inertial and energy-containing subranges of turbulence). In particular, two different formulas have recently been proposed for the second-order longitudinal structure function based on the wide energy spectrum. The comparison between these two formulas reveals significantly different predictions of the breakup phenomenon for particular conditions. It is important to use the Pope model energy spectrum (valid for the wide spectrum of turbulence) consistently (Pope, S.B., 2000. Turbulent Flows. Cambridge University Press, Cambridge). That is, parameter fitting must be performed on the parameters of the energy spectrum function when the physical conditions of the system is changed. Although the parameter values given in the original literature by Pope are valid only at sufficiently high Reynolds number, these parameter values have been employed at low Reynolds numbers by some researchers. With decreasing Reynolds numbers the difference between employing the original suggested values and re-fitted parameter values in models for breakage is increasingly significant. In the development of new models for the daughter size distribution function, the number and volume conservation properties should always be analyzed. Care should be taken when a change in the model parameter is performed, for example, the Jacobian relation in an integral is required for consistency. Precise notation regarding the function definitions is required in order to avoid model misinterpretations.


      PubDate: 2016-05-15T05:48:41Z
       
  • Dynamic modelling of homogeneously catalysed glycerol hydrochlorination in
           bubble column reactor
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Cesar A. de Araujo Filho, Debanga Mondal, Stefan Haase, Johan Wärnå, Kari Eränen, Jyri-Pekka Mikkola, Tapio Salmi
      The homogeneously catalysed glycerol hydrochlorination was thoroughly investigated in a continuous isothermal co-current bubble column reactor over a wide range of reaction parameters, such as temperature (70–120°C), catalyst concentration (3–12%), liquid flow rate (6–12mL/min) and gas flow rate (0.4–1.0L/min). The flow patterns inside the reactor were studied by means of step response residence time distribution experiments and by high-speed camera images. The fluid dynamics of the system presented an unusual behaviour due to the extremely high solubility of HCl in the reaction mixture. Interestingly, the fluid dynamics imposed severe limitations to the reaction conversion. The axial dispersion model was applied for describing the dynamic changes in concentrations of compounds. Kinetic and solubility data were collected from previous work on glycerol hydrochlorination in semi-batch reactor conducted by our research group. The bubble column model was able to successfully describe the dynamic behaviour of 29 experiments, as well as estimate hydrodynamics and mass transfer parameters.


      PubDate: 2016-05-15T05:48:41Z
       
  • On the hydrodynamics of airlift reactors, Part I: Experiments
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): T. Ziegenhein, J. Zalucky, R. Rzehak, D. Lucas
      It is more and more possible to design bubbly flow reactors with methods of the computational fluid dynamics (CFD). Measurements that can be used for model validation, however, are often missing, especially for complex setups like airlift reactors. Such measurements include locally resolved information about the dispersed and continuous phase, particularly the information about the flow field and interface structures are important. In the present work Reynolds stresses, liquid velocity and gas void fraction profiles as well as bubble size distributions are provided at several positions in the riser and the downcomer in a rectangular airlift reactor for this purpose. In addition, the hydrodynamics inside this airlift reactor are described in detail by the measured values.


      PubDate: 2016-05-15T05:48:41Z
       
  • Adsorption measurements on a CrOx/γ-Al2O3 catalyst for parameter
           reduction in kinetic analysis
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): G. Kiedorf, T. Wolff, A. Seidel-Morgenstern, C. Hamel
      This work presents an attempt to include more detailed descriptions of adsorption equilibria into the analysis of the rates of heterogeneously catalyzed reactions. The adsorption behavior of ethylene, propylene, oxygen, carbon monoxide and carbon dioxide was studied on a CrO x /γ-Al2O3 catalyst in a broader concentration and temperature range. Dynamic measurements were performed in a tubular reactor applying the Frontal Analysis method, to estimate adsorption isotherms for single components and mixtures individually. The classical Langmuir model and a bi-adsorption model consisting of a Langmuir and a Henry term were parameterized. The temperature dependence of the isotherm model parameters was described via an Arrhenius approach. Using the Multi-Langmuir model and the Ideal Adsorbed Solution Theory, competitive adsorption isotherms for ethylene and propylene were predicted based on the estimated single component parameters. However, the experimental evaluation of the predicted mixture isotherms offered no effect in the concentration range considered. In a higher concentration range the experimental competitive adsorption isotherms were significantly affected. Thus, the considered competitive adsorption models work well. Consequently, the Multi-Langmuir adsorption model is sufficient to describe the investigated model system. With the reliable mathematical description of the adsorption isotherms a more profound description of the reaction rates is possible by separating kinetic and thermodynamic effects.


      PubDate: 2016-05-15T05:48:41Z
       
  • Mixing at high Schmidt number in a complex porous structure
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Adrian Zenklusen, Saša Kenjereš, Philipp Rudolf von Rohr
      Highly porous structures (porosity ≥ 75 % ), as metal foams or designed foam-like structures, are often used in industry to augment heat and mass transfer. In the present study, we focus on the mixing in highly porous structures in continuous millireactor characterized with a relatively low Reynolds number ( Re D = 240 – based on the ligament diameter and bulk velocity) and a high Schmidt number fluid (Sc=2400). We apply a combined numerical and experimental approach. The numerical simulations employ a Large Eddy Simulation (LES) method with dynamic Lagrangian approach for subgrid-scale turbulent stress and turbulent mass flux. The results of the numerical simulation are compared with our own combined Particle Imaging Velocimetry (PIV) and Laser Induced Fluorescence (LIF) measurements. The application of combined PIV/LIF makes it possible to simultaneously measure velocity components, turbulent stresses, concentration and concentration fluxes. The mechanism of the mixing is analyzed in detail with specific focus on validity of a simple gradient diffusion hypothesis (SGDH) in modeling of the turbulent mass transfer in complex porous structure.


      PubDate: 2016-05-15T05:48:41Z
       
  • Flow and pressure characteristics in rectangular channels with internal
           cylindrical bodies
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Hendrik Gossler, Benjamin L. Kee, Huayang Zhu, Matthias Hettel, Olaf Deutschmann, Robert J. Kee
      This paper develops models for steady-state, fully developed, laminar flow in rectangular channels with internal coaxial solid cylinders. By casting and solving the parallel-flow momentum equation in a dimensionless setting, correlations are derived for the friction factor f and represented as Ref where Re is the Reynolds number. The correlations consider three positions for the internal cylinder. The cylinder may be in the center of the rectangular channel, in the corner of the channel, or resting at the middle of the channel floor. The correlations incorporate channel aspect ratios in the range 0.1 ≤ α ≤ 1.0 . The cylinder-diameter aspect ratios β range from being vanishingly small to being large enough to touch the channel walls. Although the results are general, the study is motivated by considering the effects of diagnostic probes within small channels of catalytic monoliths.


      PubDate: 2016-05-15T05:48:41Z
       
  • Slot coating minimum film thickness in air and in rarefied helium
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): H. Benkreira, J.B. Ikin
      This study assesses experimentally the role of gas viscosity in controlling the minimum film thickness in slot coating in both the slot over roll and tensioned web modes. The minimum film thickness here is defined with respect to the onset of air entrainment rather than rivulets, the reason being that rivulets are an extreme form of instabilities occurring at much higher speeds. The gas viscosity effects are simulated experimentally by encasing the coaters in a sealed gas chamber in which various gases can be admitted. An appropriate choice of two gases was used to compare performances: air at atmospheric pressure and helium at sub-ambient pressure (25mbar), which we establish has a significantly lower “thin film” viscosity than atmospheric air. A capacitance sensor was used to continuously measure the film thickness on the web, which was ramped up in speed at a fixed acceleration whilst visualizations of the film stability were recorded through a viewing port in the chamber. The data collected show clearly that by coating in rarefied helium rather that atmospheric air we can reduce the minimum film thickness or air/gas entrainment low-flow limit. We attribute this widening of the stable coating window to the enhancement of dynamic wetting that results when the thin film gas viscosity is reduced. These results have evident practical significance for slot coating, the coating method of choice in many new technological applications, but it is their fundamental merit which is new and one that should be followed with further data and theoretical underpinning.


      PubDate: 2016-05-15T05:48:41Z
       
  • Micro-model experiments and pore network simulations of liquid imbibition
           in porous media
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Yu Sun, Abdolreza Kharaghani, Evangelos Tsotsas
      In this study, spontaneous capillary imbibition into an air-filled transparent etched silicon-glass micro-model is investigated by optical imaging under ambient conditions for mixtures of ethanol and water. Images of the micro-model are acquired by a high-speed CCD camera. The binarized images allow us to obtain the overall imbibition kinetics and the time evolution of the phase distribution. A pore network with the structure parameters of the physical micro-model is generated, and a wetting algorithm that combines several pore-level liquid transport rules is developed to simulate the spontaneous imbibition of the liquid mixture into the network. The pore network simulations are able to reproduce the effects observed in the micro-model experiments. The influence of spatially correlated structural features on the imbibition dynamics is studied by further pore network simulations, and pore structures that cause weak or strong capillary imbibition are identified. The results of wetting simulations are shown for situations which cannot be treated by the Lucas–Washburn equation.


      PubDate: 2016-05-15T05:48:41Z
       
  • Process integration approaches to optimal planning of unconventional gas
           field development
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Dominic C.Y. Foo, Raymond E.H. Ooi, Raymond R. Tan, Jui-Yuan Lee
      In recent years, the oil and gas industry has been moving to develop unconventional gas fields, which include those contaminated with high carbon dioxide (CO2) content. Typically, the CO2 has to be separated from the natural gas (NG) in offshore processing facilities (in situ) before the NG can be sent for processing at the gas plant onshore. To date, commercial-scale CO2 capture and storage (CCS) has proven to be viable mainly for CO2 that is separated from NG and subsequently injected at or near the gas field itself for permanent storage (CO2 sequestration) or utilized for the purpose of Enhanced Oil Recovery (EOR). In the case of multiple adjacent reservoirs exhibiting variations in NG quality and CO2 content, it may be necessary to have in situ CO2 removal using NG sweetening processes (e.g. membrane or amine absorption) to achieve a quality level such that the pooled NG streams meets the sales gas specification required for further processing at an onshore facility for sales. In this work, new process integration approaches are proposed to aid in the integrated planning of such joint field development projects, to rationalize the development of contaminated gas fields together with conventional sweet gas fields in meeting the required sales gas specifications of CO2 content. These approaches are based on analogous techniques previously developed for distributed effluent treatment systems and carbon capture planning for the power generation sector. A case study is used to illustrate how general insight-based policies for gas field development can be drawn from process integration perspectives.
      Graphical abstract image

      PubDate: 2016-05-15T05:48:41Z
       
  • Hydrolysis kinetics of inulin by imidazole-based acidic ionic liquid in
           aqueous media and bioethanol fermentation
    • Abstract: Publication date: 12 September 2016
      Source:Chemical Engineering Science, Volume 151
      Author(s): Zhi-Ping Zhao, Xiao-Lan Wang, Gui-Yin Zhou, Yong Cao, Peng Lu, Wen-Fang Liu
      This article focused on the inulin-containing energy biomass, Jerusalem artichoke, to explore environment-friendly processes for bioethanol production. An imidazole-based acidic ionic liquid (VImaILs) was prepared as the catalyst of inulin hydrolysis in aqueous media. The hydrolysis kinetics was studied under different conditions. The kinetic parameters of hydrolysis by VImaILs and dilute sulfuric acid were estimated and compared. This work demonstrated that the hydrolysis rate of inulin into reducing sugars by VImaILs was obviously faster than that by the latter. The proposed kinetic model successfully predicted the inulin hydrolysis in wider ranges of experimental conditions. The hydrolysate was fermented into ethanol by Saccharomyces cerevisiae which activity was not inhibited by the VImaILs. The conversion efficiency of inulin-type sugars to ethanol was greater than 92.5% of the theoretical yield. And the ethanol production capacity reached 123.76g/(L). This system integrated the chemical and biological processes to prepare ethanol in an environment-friendly way.
      Graphical abstract image

      PubDate: 2016-05-15T05:48:41Z
       
  • Activity based kinetics of CO2–OH− systems with Li+, Na+ and
           K+ counter ions
    • Abstract: Publication date: 12 September 2016
      Source:Chemical Engineering Science, Volume 151
      Author(s): Shahla Gondal, Hallvard F. Svendsen, Hanna K. Knuutila
      In this work the applicability of activity based kinetics for the absorption of CO2 into hydroxide and carbonate solutions is discussed. It was found by several authors that reaction rate constants based on concentration strongly depend both on concentration and the counter ion present in solution. In this study experimental kinetics data for LiOH, NaOH and KOH from the literature were reevaluated using activity based kinetics. It is observed that the use of activities instead of concentrations eliminates the effect of both concentration and counter ion on the rate constant and an expression for the activity based second order rate constant is derived. The activities used in this work were calculated with the electrolyte-NRTL model which predicts well the equilibrium partial pressure of CO2, the composition of the liquid phase and the apparent Henry’s law constant. The calculated activity coefficients were used to predict the activity based rate constant and CO2 flux from the concentration based second order kinetic constant at infinite dilution ( k OH − ∞ ). The infinite dilution rate constant, combined with e-NRTL based activities of CO2 and hydroxyl ion, predicted the CO2 absorption fluxes within 14% AARD showing that the proposed approach can be used for prediction of activity based rate constants and the CO2 absorption flux for any system involving the reaction of CO2 with hydroxyl ion.


      PubDate: 2016-05-15T05:48:41Z
       
  • Sub-grid models for heat transfer in gas-particle flows with immersed
           horizontal cylinders
    • Abstract: Publication date: 12 September 2016
      Source:Chemical Engineering Science, Volume 151
      Author(s): W.A. Lane, A. Sarkar, S. Sundaresan, E.M. Ryan
      Simulating full-scale heated fluidized bed reactors can provide invaluable insight to the design process. Such simulations are typically computationally intractable due to their complex multi-physics and various length-scales. While it may be possible to simulate some large-scale systems, they require significant computing resources and do not lend themselves well to design optimization methods. To overcome these problems coarse-grid simulations can be used with supplementary constitutive sub-grid models to approximate the unresolved physics. This study details the development, implementation, and verification of a sub-grid model for heat transfer in gas-particle flows with immersed horizontal cylinders. Using the two-fluid model for multiphase flow, small periodic unit-cell domains were simulated over a wide range of flow and geometry conditions. The results were filtered and fit using nonlinear regression to build a Nusselt correlation based on the solids fraction, solids velocity, cylinder geometry (diameter and spacing), and the Peclet number. The proposed model is highly nonlinear and includes power-law contributions from each parameter. The model was verified using a nearly orthogonal experiment design where the input parameters were varied randomly to generate combinations not previously considered. The predicted filtered Nusselt numbers agreed well with the observed (simulated) values. Work is on-going to further expand the capabilities of the model, including 3D simulations, vertical cylinders, and uncertainty quantification.


      PubDate: 2016-05-15T05:48:41Z
       
  • Prediction of segregation in funnel and mass flow discharge
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Davide Bertuola, Silvia Volpato, Paolo Canu, Andrea C. Santomaso
      In this paper we present a model to predict the onset and evolution of segregation during the discharge of binary mixtures of granular materials. The model accounts for the multi-phase and multi-component nature of the granular mixtures, to simulate the main flow regimes occurring in the discharge of silos (funnel and mass flow) and how they affect segregation. The new comprehensive model for segregation follows a continuum Eulerian approach and results from the coupling between an ad-hoc rheology for granular flow and a percolation model for multi-component mixtures. Predictions are compared with independent literature experimental data, for short and tall silos and prove to be quite accurate, after a tuning of the percolation flux sub-model. The larger segregation in short flow paths with smaller amount of fines reported by the experiments is quantitatively predicted. The model also predicts the three phases observed in experiments during the discharge of tall silos.


      PubDate: 2016-05-08T16:15:21Z
       
  • Efficient tracing and stability analysis of multiple stationary and
           periodic states with exploitation of commercial CFD software
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): E.D. Koronaki, G.P. Gakis, N. Cheimarios, A.G. Boudouvis
      A computational approach is presented that enables commercial Computational Fluid Dynamics (CFD) codes to detect Hopf bifurcations and with necessary adjustments, compute the frequency and amplitude of the periodic orbits that arise from the Hopf point. The proposed computational framework, which combines a homemade Matlab code with Ansys/Fluent, is an extension of a previously presented methodology for the efficient tracing of solution branches that contain turning points. The need for the special attention to periodic orbits springs from recently published results that indicate that time-periodic states occur in industrial-scale Chemical Vapor Deposition (CVD) reactors. Nevertheless the method presented here is not limited to deposition processes; in fact it treats the CFD process model as a “black box” and requires no alteration of the commercial software. To prove the effectiveness of the computational framework, it is implemented here on the benchmark case of laminar flow around a cylinder, where Hopf bifurcations have been identified via eigenvalue analysis. Once the method is validated, it is implemented on a rotating-disk commercial CVD reactor model in the region of parameter space where Hopf points are observed. In both the benchmark and the industrial-scale CVD cases, stable and unstable, stationary and periodic states are computed for the same parameter values.


      PubDate: 2016-05-08T16:15:21Z
       
  • Modeling of the interaction among aerobic ammonium-oxidizing
           archaea/bacteria and anaerobic ammonium-oxidizing bacteria
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Yuting Pan, Bing-Jie Ni, Yiwen Liu, Jianhua Guo
      Biological nitrogen removal by using a co-culture of Anammox bacteria, ammonia-oxidizing archaea (AOA) and (ammonia-oxidizing bacteria) AOB microorganisms in a sequencing batch reactor (SBR) has previously been demonstrated experimentally. In this work, a mathematical model is developed to describe the microbial interaction among AOA, AOB and Anammox bacteria in the single-stage SBR and provide the first insights on the key role of AOA in such system. In this model, AOA and AOB jointly convert ammonium to nitrite partially, which provides electron acceptors to Anammox bacteria to oxidize the remaining ammonium forming dinitrogen gas. The model is successfully calibrated and validated using the long-term (around 350 days) dynamic experimental data from the SBR system, as well as two independent batch tests at different operational stages of the SBR. The model satisfactorily describes the nitrogen conversion data from the system. Modeling results show that AOA would outcompete AOB under low ammonium concentration and low dissolved oxygen conditions due to the revealed higher NH4 + affinity ( K N H 4 A O A of 0.06g Nm−3) and thus higher ammonia oxidation rate under oxygen-limited conditions, indicating that AOA could be a better partner to Anammox bacteria compared to AOB when treating low strength nitrogen sewage. The developed model could also predict and distinguish the different contributions of AOA and AOB to overall aerobic ammonia oxidizing potential, with more than 50% of ammonia oxidation being mediated by AOB at initial stage (~300 days) and AOA being responsible for up to 90% of the ammonium removal afterwards. The results suggest AOA coupled with Anammox could provide new possibilities for biological nitrogen removal from low strength ammonium wastewater.


      PubDate: 2016-05-08T16:15:21Z
       
  • A theoretical comparison of multifunctional catalyst for sorption-enhanced
           reforming process
    • Abstract: Publication date: 21 August 2016
      Source:Chemical Engineering Science, Volume 150
      Author(s): Elva L. Lugo, Benjamin A. Wilhite
      This work presents the first side-by-side comparison of the two leading multifunctional catalyst designs reported in the literature today for sorption-enhance reforming processes. Two-dimensional unsteady-state models were developed to compare the performance of a core–shell multifunctional catalyst, consisting of a calcium-based sorbent core enclosed in a porous shell of methane steam reforming or water-gas shift catalyst, against an equivalent case of a uniform-distributed multifunctional design in which catalyst and sorbent materials are uniformly distributed within the particle. Additionally, these two multifunctional catalyst designs were compared against the conventional two-pellet approach, where the capture and catalytic properties are distinguished into separate pellets. Both multifunctional catalyst designs (i.e. core-shell and uniform-distributed) had greater adsorbent utilization and higher H2 outlet concentration up to breakthrough time than the conventional two pellet design. The uniform-distributed multifunctional catalyst design had greater adsorbent utilization up to breakthrough conditions as compared to the core-shell design. This behavior may be attributed to the fact that for the uniform-distributed multifunctional, the active catalyst is constantly producing CO2 next to an adsorbent active site. For the core-shell multifunctional catalyst design, decreasing catalyst-shell thickness resulted in performance approaching the uniform-distributed case. For the case of exothermic water-gas shift reaction coupled with CO2 chemisorption, the core-shell design mitigated local bed hot-spot magnitudes by ~40K.


      PubDate: 2016-05-08T16:15:21Z
       
  • Flocculation of fine hematite and quartz suspensions with anionic
           cellulose nanofibers
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Kalle Kemppainen, Terhi Suopajärvi, Ossi Laitinen, Ari Ämmälä, Henrikki Liimatainen, Mirja Illikainen
      Research was undertaken to investigate the efficiency of anionic dicarboxylic acid (DCC) and sulfonated (ADAC) cellulose nanofibers in flocculating fine hematite and quartz particles. Flocculation was studied at pH levels varying from 5 to 10 and chemical dosages of 0–2000ppm, with turbidity measurements after sedimentation and with analytical centrifugation after a short intense mixing stage. Results showed that DCC and ADAC cellulose nanofibers did not flocculate quartz within pH range 5–10 but were able to flocculate hematite. DCC's ability to flocculate hematite and the ability of formed flocs to withstand the shear forces of subsequent intense stirring depended markedly on the pH of the suspension. The most effective performance was obtained at a pH of 8–9, and a DCC dosage of 200–500ppm was enough to flocculate hematite efficiently. In addition, unlike ADAC nanofibers, DCC nanofibers were able to flocculate hematite under short vigorous stirring. ADAC nanofibers proved to be as efficient a hematite flocculant as DCC nanofibers at a dosage of 500ppm after longer conditioning time and less vigorous stirring. Furthermore, the operational pH region was wider for ADAC nanofibers, and the hematite flocs did not show any pH-dependent breakage.


      PubDate: 2016-05-03T12:24:21Z
       
  • Microfluidic solvent extraction of rare earth elements from a mixed oxide
           concentrate leach solution using Cyanex® 572
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Elisabeth Kolar, Rik P.R. Catthoor, Frederik H. Kriel, Rossen Sedev, Scott Middlemas, Eric Klier, Gareth Hatch, Craig Priest
      Solvent extraction of rare earth elements (REEs) involves hundreds of individual extraction and phase separation cycles, fine adjustment of solution conditions, and individual stage and overall process times that are long. Therefore, we investigated microfluidic solvent extraction (microSX) of REEs from a leached mixed rare earth oxide (REO) mineral concentrate using a phosphorus-based cationic exchange extractant (Cyanex® 572). A Y–Y microchip was used, in which the aqueous and organic phases were contacted for up to 15s with sub-second resolution. The extraction rate and selectivity for heavy REEs was determined for the prepared leach solution. Good selectivity for heavy REEs was observed using the microchip for leach solutions adjusted to pH 0.7. Extraction rates on the microchip were typically double that observed in conventional (bulk) solvent extractions, except for Lu and Yb, which were three-times faster. The faster extraction can be largely attributed to the higher surface-to-volume ratio achieved in our microfluidic experiments; double that observed for bulk extractions under the conditions employed.
      Graphical abstract image

      PubDate: 2016-05-03T12:24:21Z
       
  • Autothermal reverse-flow reactors: Design and comparison of valve-operated
           and rotary systems
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Carlos Daniel Luzi, Osvaldo Miguel Martínez, Guillermo Fernando Barreto
      The valve-operated reverse-flow catalytic reactor is an efficient system for the treatment of air streams contaminated with small amounts of volatile organic compounds (VOCs). Nonetheless, it has two drawbacks when operated at low cycle periods: the emission of the volume without treatment present in the region close to the reactor input and an unavoidable reduction of the valve lifetime. Upon consideration that the use of shorter cycle periods would enable the design of more compact units, we investigated the option of operating with reverse flow by means of a rotary catalytic reactor. This alternative eliminates the necessity of valves for the flow reversal and enables to allot a small fraction of the total cross section to be fed with clean air and prevent the VOCs that remain close to the reactor input from being discharged to the atmosphere. The aim of this work is to analyse the treatment of an air stream contaminated with ethanol and ethyl acetate by means of mathematical simulation of reverse-flow operations in both valve-operated and rotary catalytic reactors. To that end, monolithic structures with square channels are assumed for both types of reverse-flow reactors, a design strategy is proposed and the results for both types of reactors are compared. It is concluded that the rotary reverse-flow reactor arises as a better option.


      PubDate: 2016-05-03T12:24:21Z
       
  • The thermal electrolytic production of Mg from MgO: A discussion of the
           electrochemical reaction kinetics and requisite mass transport processes
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): N. Leonard, M. Korenko, C. Larson, K. Blood, L.J. Venstrom, S. Nudehi, S. Duncan, R. Diver, F. Simko, J. Priscak, J. Schoer, P.T. Kissinger, R. Palumbo
      We examined the kinetic and transport processes involved in Mg production from MgO via electrolysis at ca 1250K with in a eutectic mixture of MgF2–CaF2, using a Mo cathode, and carbon anode. Exchange current densities, transfer coefficients, and diffusion coefficients of the electroactive species were established using a combination of cyclic and linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The cathode kinetics are described by a concentration dependent Butler–Volmer equation. The exchange current density and cathodic transfer coefficient are 11±4Acm−2 and 0.5±0.12 respectively. The kinetics of the anode are described by two Tafel equations: at an overvoltage below 0.4V, the exchange current density is 0.81±0.2mAcm−2 with an anodic transfer coefficient of 0.5±0.1; above 0.4V overvoltage the values are 0.14±0.05mAcm−2 and 0.7±0.2 respectively. The diffusion coefficients of the electroactive species are D(Mg2+)=5.2±0.6E−5cm2 s−1 and D( Mg 2 OF 4 2 - )=7.2±0.2E−6cm2 s−1. The ionic conductivity of the electrolyte is ca 2.6Scm−1. A 3D finite element model of a simple cell geometry incorporating these kinetic and transport parameters suggest that up to 27% of the energy required to drive the electrolysis reaction can be supplied thermally for a current density of 0.5Acm−2, enabling a reduction in operating cost if the thermal energy is substituted for valuable electric work.


      PubDate: 2016-05-03T12:24:21Z
       
  • Enhanced modelling of heterogeneous gas–solid reactions in acid gas
           removal dry processes
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Giacomo Antonioni, Alessandro Dal Pozzo, Daniele Guglielmi, Alessandro Tugnoli, Valerio Cozzani
      Acid gases as hydrogen halides and sulphur oxides are typical pollutants of combustion processes. Their removal from flue gas can be performed via the injection of dry powdered sorbents, as calcium hydroxide. However, the efficiency of dry treatment methods is hindered by the limited final conversion of the solid reactant, due to an abrupt decline of its reactivity during the reaction process. Fundamental gas–solid reaction models such as the shrinking core model and the grain model are able to reproduce this phenomenon only introducing an arbitrary value of the final conversion or an adjustable value of the solid-state diffusivity of the gaseous reactant. In the present study, the conventional grain model approach was integrated with a crystallisation and fracture (CF) submodel, which links the chemical potential of nucleation to the work needed to displace the layer of solid product formed on the reaction interface. The decline in reactivity of the sorbent was accounted by a twofold effect of the product layer growth: (i) the increase of the characteristic length for solid-state diffusion, accounted for in the grain model, and (ii) the increase of the mechanical work required for nucleation as a function of product layer thickness, accounted for in the CF submodel. This approach, validated against literature data on the Ca(OH)2/HCl system, allowed reproducing the conversion of the solid reactant at different operating temperatures.


      PubDate: 2016-05-03T12:24:21Z
       
  • Dissociation of natural and artificial gas hydrate
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): S.Y. Misyura, I.G. Donskoy
      Dissociation kinetics of natural and artificial methane hydrate were studied experimentally and theoretically. The artificial methane hydrate was produced in the reactor, and the natural clathrate was extracted from the bottom of Lake Baikal. The behavior of the natural gas hydrate decay is markedly different from the artificial one under non-isothermal conditions. For natural methane hydrates there is a much longer self-conservation area and a lower rate of dissociation caused by different initial defectiveness of samples. The proposed model takes into account the area of self-conservation and structural characteristics of the granules that allows qualitatively and quantitatively describing the dissociation. The non-isothermal dissociation was numerically simulated, taking into account heat and mass transfer, kinetics of phase transformation, gas filtering inside the granules and porous characteristics (size and density of pores). Different requirements are applied to technologies for efficient storage and combustion of gas hydrates. A more stable region of self-conservation of natural gas hydrate increases the efficiency of its storage and transportation. In this case, a durable crust of ice with a low concentration of pores is achieved for higher temperatures than for the artificially synthesized hydrate. In the course of dissociation of gas hydrate at negative temperatures of annealing, the density of the pores distribution in the formed ice crust decreases by eight orders that significantly changes the rate of decay during the dissociation. The simulation of dissociation of natural and artificial methane hydrates was implemented with a maximum density of pores and well agreed with the experimental data. Thus, it has been experimentally and theoretically shown that the density and size of pores dramatically affect the kinetics of dissociation. During storage, transportation and combustion of combustible gases solid hydrates it is necessary to determine the heat transfer coefficient and the temperature difference ∆T both for the outer medium (external boundary conditions) and the internal one (a layer of powder or pressed pellets). The dissociation rate of gas hydrates at negative temperatures T<0°С is much more complex than for T>0°С and currently there are no reliable calculation methods. The use of filtration model and structural parameters can effectively predict the behavior of gas hydrates at negative temperatures.


      PubDate: 2016-05-03T12:24:21Z
       
  • Review of gasification fundamentals and new findings: Reactors, feedstock,
           and kinetic studies
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Nader Mahinpey, Arturo Gomez
      The purpose of this work is to comprehensively review recent findings on gasification kinetics related to the reaction mechanism, the effects of the experimental procedure on the overall reaction, and methods to evaluate kinetic models. Understanding the recent findings in gasification requires the presentation of selected publications that cover several potentially ambiguous concepts. Firstly, conventional reactor definitions are not sufficient given that three reactions (combustion, pyrolysis and gasification) occur in an industrial gasifier. Secondly, variables affecting char reactivity during gasification show that the char surface area is the most complex variable to analyze. Also, single-step kinetic models provide better descriptions of the reaction mechanism assuming kinetic control of the overall reaction. The new findings are related to the gasification reaction mechanism and the interpretation of kinetic results: (a) the maximum gasification rate observed is a consequence of the gas concentration development upon changing the inert gas for the gasifying agent, and not due to changes in the char surface during gasification, as proposed by Bhatia and Perlmutter in 1980; (b) increasing the time of holding the char at the reaction temperature in an inert gas decreases the gasification rate; (c) char micropore surface area and alkali content are the two most important variables affecting the gasification rate; and, (d) laboratory studies may not represent the real gasification mechanism under kinetically controlled conditions due to the presence of mass transfer limitations from interparticle diffusion. Therefore, the acceptance of intrinsic kinetics reported in the literature should be revalidated.


      PubDate: 2016-05-03T12:24:21Z
       
  • CFD modeling and control of a steam methane reforming reactor
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Liangfeng Lao, Andres Aguirre, Anh Tran, Zhe Wu, Helen Durand, Panagiotis D. Christofides
      This work initially focuses on developing a computational fluid dynamics (CFD) model of an industrial-scale steam methane reforming reactor (reforming tube) used to produce hydrogen. Subsequently, we design and evaluate three different feedback control schemes to drive the area-weighted average hydrogen mole fraction measured at the reforming tube outlet ( x ¯ H 2 outlet ) to a desired set-point value ( x ¯ H 2 set ) under the influence of a tube-side feed disturbance. Specifically, a CFD model of an industrial-scale reforming tube is developed in ANSYS Fluent with realistic geometry characteristics to simulate the transport and chemical reaction phenomena with approximate representation of the catalyst packing. Then, to realize the real-time regulation of the hydrogen production, the manipulated input and controlled output are chosen to be the outer reforming tube wall temperature profile and x ¯ H 2 outlet respectively. On the problem of feedback control, a proportional (P) control scheme, a proportional-integral (PI) control scheme and a control scheme combining dynamic optimization and integral feedback control to generate the outer reforming tube wall temperature profile based on x ¯ H 2 set are designed and integrated into real-time CFD simulation of the reforming tube to track x ¯ H 2 set . The CFD simulation results demonstrated that feedback control schemes can drive the value of x ¯ H 2 outlet toward x ¯ H 2 set in the presence of a tube-side feed disturbance and can significantly improve the process dynamics compared to the dynamics under open-loop control.


      PubDate: 2016-05-03T12:24:21Z
       
  • In-situ crystal morphology identification using imaging analysis with
           application to the L-glutamic acid crystallization
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Yan Huo, Tao Liu, Hui Liu, Cai Y. Ma, Xue Z. Wang
      A synthetic image analysis strategy is proposed for in-situ crystal size measurement and shape identification for monitoring crystallization processes, based on using a real-time imaging system. The proposed method consists of image processing, feature analysis, particle sieving, crystal size measurement, and crystal shape identification. Fundamental image features of crystals are selected for efficient classification. In particular, a novel shape feature, referred to as inner distance descriptor, is introduced to quantitatively describe different crystal shapes, which is relatively independent of the crystal size and its geometric direction in an image captured for analysis. Moreover, a pixel equivalent calibration method based on subpixel edge detection and circle fitting is proposed to measure crystal sizes from the captured images. In addition, a kernel function based method is given to deal with nonlinear correlations between multiple features of crystals, facilitating computation efficiency for real-time shape identification. Case study and experimental results from the cooling crystallization of l-glutamic acid demonstrate that the proposed image analysis method can be effectively used for in-situ crystal size measurement and shape identification with good accuracy.


      PubDate: 2016-05-03T12:24:21Z
       
  • Numerical investigation on the effect of draft plates on spouting
           stability and gas–solid characteristics in a spout-fluid bed
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Shiliang Yang, Yuhao Sun, Liangqi Zhang, Ya Zhao, Jia Wei Chew
      Numerical simulation of dense gas–solid motion in a spout-fluid bed was carried out using the computational fluid dynamics coupled with discrete element method (CFD–DEM), in which the gas and solid motion are solved in the Eulerian and Lagrangian framework, respectively. After validating the simulated results with experimental data, the main cause of spouting instability was first identified, followed by evaluating the effect of draft plate length on spouting stability, pressure signals, and gas–solid hydrodynamics in the system. The results demonstrate that the onset of spout dancing, which is a type of spouting instability, is primarily due to the merging of the rising bubbles in the annulus with the spouting channel, which can be circumvented by the presence of draft plates. Increasing the draft plate length diminishes the mean pressure in the spouting inlet and the corresponding peak value of the power spectrum, and the correlation coefficient of pressure signals in the spout and background inlets. Regarding effect on the gas–solid hydrodynamics, a longer draft plate length leads to a more dilute upper spout, a higher spoutable height, higher voidage in the central fountain region, higher vertical gas flux (Fgz) and solid velocity (Usz) in the central axis, lower Fgz and Usz near the wall, and lower vertical solid flux (Fsz) overall. The optimization of the draft plate length depends on a balance between spout stability and solid circulation rate, since the former increases but the latter decreases with draft plate length.


      PubDate: 2016-05-03T12:24:21Z
       
  • Ethane selective adsorbent Ni(bdc)(ted)0.5 with high uptake and its
           significance in adsorption separation of ethane and ethylene
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Wanwen Liang, Feng Xu, Xin Zhou, Jing Xiao, Qibin Xia, Yingwei Li, Zhong Li
      We reported a novel ethane selective metal–organic framework material Ni(bdc)(ted)0.5 with a high uptake of C2H6 and a decent selectivity towards C2H6/C2H4 separation. This material was synthesized with double ligands (bdc and ted) by a hydrothermal method. Its C2H6 and C2H4 isotherms were subsequently measured. The BET surface area of the synthesized Ni(bdc)(ted)0.5 reached 1701m2/g. Successful assembling of the two organic ligands into Ni(bdc)(ted)0.5 was indicated by FT-IR. TGA indicated that Ni(bdc)(ted)0.5 was stable in the temperature region below 673K. Ni(bdc)(ted)0.5 exhibited decent adsorption capacities of C2H6 and C2H4 with a superior high C2H6 adsorption capacity of 6.93mmol/g at 100kPa. More importantly, it exhibited preferential adsorption of C2H6 over C2H4. Its C2H6/C2H4 adsorption selectivity was in the range of 2–7.8 at pressure below 100kPa, higher than the reported adsorbents possessing the characteristic of preferential adsorption of C2H6 over C2H4. In addition, the isosteric heat of C2H6 and C2H4 adsorption on Ni(bdc)(ted)0.5 were much lower compared to those π-complexation sorbents adsorbing olefin preferentially by binding with the π bond of olefin. The high ethane adsorption capacity, high ethane/ethylene selectivity and low isosteric heat of adsorption of Ni(bdc)(ted)0.5 would make it a promising adsorbent for the effective separation of ethane/ethylene.
      Graphical abstract image

      PubDate: 2016-05-03T12:24:21Z
       
  • Table of Contents
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148




      PubDate: 2016-05-03T12:24:21Z
       
  • Modelling size distribution changes of plant cell aggregates during batch
           growth of Capsicum frutescens suspension culture
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148
      Author(s): Ferda Mavituna, Sung-Yong H. Yoon, Jong M. Park
      The aim of this work was to develop a theoretical model and its computer simulation for the prediction of plant cell aggregate size distribution change with time in batch suspension cultures. We combined the theory of the particle size distribution with the Monod kinetics to describe the plant cell aggregate growth. Since plant cell aggregates can grow to be large, we also included in the model the option to account for the intra-particle molecular diffusional resistance to glucose which was the carbon substrate needed for growth. We obtained the values of the kinetic parameters from the batch growth of Capsicum frutescens (chilli pepper) cell cultures. The maximum specific growth rate was 0.31 day–1 and the Monod constant 16.67gL–1. We also measured the aggregate size distributions during batch growth which covered a range of 0.25–7.5mm. Despite the simplifying assumptions, the simulated size distribution curves followed the experimental trends reasonably. The intra-aggregate mass transfer resistance became important only for the later stages of the batch culture. The model and computer algorithms can serve as a starting point and can be adapted to investigate other plant, animal and microbial systems that show aggregated growth behaviour.
      Graphical abstract image

      PubDate: 2016-05-03T12:24:21Z
       
  • Editorial Board
    • Abstract: Publication date: 12 July 2016
      Source:Chemical Engineering Science, Volume 148




      PubDate: 2016-05-03T12:24:21Z
       
  • Enrichment of ventilation air methane by adsorption with displacement
           chromatography technology: Experiment and numerical simulation
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Ying Yang, Yijiang Wu, Haiqing Liu, Ana Mafalda Ribeiro, Ping Li, Jianguo Yu, Alirio E. Rodrigues
      Using the principles of displacement chromatography, a cost-effective adsorption separation method for the recovery of ventilation air methane (VAM) is developed. A fixed bed with activated carbon beads (ACBs) is used to adsorb low-concentration methane from VAM gas. The stronger adsorption component CO2 passes through the column to displace the adsorbed CH4. This displacement step generates a product with highly pure CH4 gas. Adsorption equilibrium isotherms of CH4, N2 and CO2 have been measured gravimetrically at different temperatures up to 10bar. These isotherms are fitted to the Sips model. Diluted breakthrough results are analyzed using a bi-pore diffusion model to obtain the micropore diffusivities of CH4, N2 and CO2 in the ACBs. Mixture breakthrough results have been employed to validate the applicability of the IAST-Sips model to predict mixture adsorption equilibria. A rigorous mathematical model is used to investigate the evolution curves of CH4, N2 and CO2 along the fixed bed during the CO2 displacement step, where it is found that the enrichment of the low concentration CH4 is improved significantly. Furthermore, the CO2 displacement experiments in the fixed bed for methane recovery from CH4/N2 mixtures with 1% and 10% CH4 content are performed and compared with the simulated results. It is found that 10% CH4 gas is concentrated to 89% CH4 purity and 1% CH4 gas can be concentrated to 53.5% CH4 purity, demonstrating that CO2 displacement is a promising technology for the enrichment of ventilation air methane.


      PubDate: 2016-05-03T12:24:21Z
       
  • Analysis of milling of dry compacted ribbons by distinct element method
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): C. Hare, M. Ghadiri, N. Guillard, T. Bosworth, G. Egan
      Fine cohesive powders are often dry granulated to improve their flowability. Roller compaction is commonly used to produce dense ribbons which are then milled. The material properties of the powder and the conditions in the roller compactor affect the strength of the ribbons, however there is no method in the literature to predict the size distribution of the product of ribbon milling. Here we introduce a method, by using the Distinct Element Method (DEM) to determine the prevailing impact velocities and stresses in the mill, with bonded spheres representing the ribbons. The bond strength is calibrated by matching experimental results of three point bend measurements and predictions from numerical simulations. The ribbons are then exposed to the dynamic conditions predicted by the DEM, by dropping them from a controlled height to cause fragmentation, and subsequently stressing them in a shear cell under the conditions again predicted by the DEM. The fragments are sheared under these conditions to represent repeated passage of bars over the fragments at the mill base. Sieve analysis is used here to determine the particle size distribution under given mill conditions. The predicted size distribution of the mill product compares well with the plant data. It is found that the mill speed and length of ribbons fed to the mill have no significant influence on the product size distribution for the range tested.
      Graphical abstract image

      PubDate: 2016-05-03T12:24:21Z
       
  • Jet loop reactors as a versatile reactor set up - Intensifying catalytic
           reactions: A review
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Helge Warmeling, Arno Behr, Andreas J. Vorholt
      To overcome the challenges of the increasing global energy and feedstock prices intensified process equipment is one way to develop new efficient production pathways for the chemical industry. In this article the authors convey a thorough overview about the jet loop reactor technique. Ensuing an introduction the operation principle of the reactor type is elucidated. Information available in the literature regarding dimensioning and the physical description is summarized in the following to give an outline of constructional possibilities. To underline the main advantages of the set up the macro and micro mixing properties are discussed in detail and exemplary data is presented. Applied chemical and biochemical reactions are reviewed, with particular focus on the enhancement of catalytic reactions subdivided in homogenously, heterogeneously and biocatalyzed conversions.
      Graphical abstract image

      PubDate: 2016-05-03T12:24:21Z
       
  • On wetting characteristics of droplet on a spherical particle in film
           boiling regime
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Subhasish Mitra, Thi Bang Tuyen Nguyen, Elham Doroodchi, Vishnu Pareek, Jyeshtharaj Bhalchandra Joshi, Geoffrey Michael Evans
      This study reports droplet-particle interaction of size ratio less than unity in the film boiling regime on a highly thermally conductive spherical particle surface. Specifically, the effects of impact Weber number (We) of subcooled state droplets comprising water (We=3.9–103.6) and isopropyl alcohol (IPA) (We=8.6–194.6) were studied using high speed imaging technique in the particle temperature range of 250–350°C. In general, non-wetting interaction behaviour was observed with two distinct outcomes – rebound and complete disintegration demarcated by a critical Weber number range instead of a single threshold value. Extent of surface wetting was characterised by the maximum droplet spread diameter parameter which was found to scale with impact Weber number in a power law form which agrees with the theoretical scaling argument. Additionally, an energy balance model was developed to compute this parameter which provided good agreement with the experimental measurements in the lower Weber number regime, however, higher deviations were noted near the transition regime. Also quantified from experiments was the droplet-particle contact time which exhibited a power law dependency on Weber number in the rebound regime, however, was noted to be almost independent of Weber number in the disintegration regime. Particle surface wettability was characterised by the experimentally measured dynamic contact angles which were found to vary in the range of 120–160o in low Weber number regime manifesting the hydrophobic nature of particle surface in film boiling regime. Also, all the parameters such as contact line velocity, particle temperature and droplet size apparently had relatively insignificant influence on the variation of dynamic contact angle. Temporal variation of non-dimensional spreading parameter exhibited a self-similar behaviour wherein all data collapsed on a single power law profile. It was further shown that the behaviour could also be described by a recovery type exponential profile through suitable non-dimensionalization and both profiles can be utilized to produce a spreading kinetics.
      Graphical abstract image

      PubDate: 2016-04-28T01:20:15Z
       
  • Three dimensional flow of liquid transfer between a cavity and a moving
           roll
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Diego M. Campana, Sebastián Ubal, María D. Giavedoni, Fernando A. Saita, Marcio S. Carvalho
      Gravure printing is one of the most promising technologies for high volume production of printed electronics and microscale films and devices. The characteristics of the printed pattern, i.e. ink volume, resolution and pattern placement (registration), are directly related to the fluid mechanics of the liquid transfer process from a cell to a substrate wrapped around a rotating roll; the liquid transfer is mainly controlled by free surfaces and dynamic contact lines. Most of the available analyses are restricted to axisymmetric flows, at which the relative motion between the cavity and the substrate is greatly simplified. Recent results have shown that the use of the complete description of the relative motion in a roll-to-roll process is critical to obtain accurate results on the amount of liquid that is transferred to the substrate. In this work we present an extension of the model describing liquid transfer from a groove to a substrate in a R2R process in order to consider the liquid transfer from a small individual cell; to this end we solve a full 3D free surface flow with moving contact lines. The results show that the liquid transfer dynamics is governed by two different characteristic time scales, one is associated with the contact line motion and the other with liquid filament breakup. Both are dependent on the capillary number. The predictions show how the volume, registration and shape of the printed dot varies with operating conditions and liquid properties. These predictions could be helpful in designing high precision printing operations.
      Graphical abstract image Highlights

      PubDate: 2016-04-28T01:20:15Z
       
  • Ultra-fast microfluidic mixing by soft-wall turbulence
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): V. Kumaran, P. Bandaru
      Slow cross-stream mixing in micro-fluidic devices poses a significant challenge in realising efficient lab-on-a-chip technologies. Due to the small dimension and flow velocity, the flow is in the laminar regime, and this results in slow molecular cross-stream diffusion (in contrast to the fast turbulent mixing by cross-stream eddies in industrial applications). Here, we demonstrate a simple and powerful strategy for ultra-fast mixing in a microchannel with one soft wall with height as low as 35μm at a Reynolds number as low as 226. There is a spontaneous transition from a laminar flow to a turbulent flow state when the flow rate increases beyond a threshold value, resulting in complete cross-stream mixing. After transition, the mixing time across a channel of width 0.5mm is smaller, by a factor of 105, than that for a laminar flow, and complete mixing is achieved within a channel length of 2cm. The increased mixing rate comes at very little energy cost, because the pressure drop is comparable to that required in current microfluidic devices, and it increases continuously and modestly at transition. This is because the channel length required to achieve complete mixing, 2cm, is much smaller than that used in microfluidic devices that employ diffusive mixing; in addition, the deformation of the soft wall decreases the resistance to flow.


      PubDate: 2016-04-28T01:20:15Z
       
  • Monte Carlo simulations of phase equilibria and microstructure of
           thiophene/[Bmim][PF6]/CO2
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Yongping Zeng, Jie Jin, Chunfeng Wang, Yueyang Xu, Jilong Wang, Shengui Ju
      Monte Carlo simulations were carried out to calculate the phase behavior of thiophene in the binary and ternary mixtures of 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) and carbon dioxide using a united atom model. The calculated pure ionic liquid densities and structural properties of [Bmim][PF6] as well as the vapor pressure of thiophene in the ionic liquid were compared with the available experimental data in the literatures, and a good agreement was obtained. Based on the radial distribution functions (RDFs) and spatial distribution functions (SDFs) results, thiophene molecules prefer to organize around the C10 atom of the butyl chain connected with the imidazolium ring. The concept of local composition in solutions was used to better understand the solution structure. It is shown that thiophene molecules can strongly associate with the cation. For the ternary system of CO2/thiophene/IL, CO2 can affect the solubility of thiophene in ionic liquid when the pressure is changed. CO2 molecules interact with the anion stronger than thiophene molecules. This implies that CO2 can be used as a potential recovery desorbent of thiophenic compounds in the ionic liquid by tuning the pressure.


      PubDate: 2016-04-28T01:20:15Z
       
  • A study of wavy falling film flow on micro-baffled plate
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Hideaki Ishikawa, Shinichi Ookawara, Shiro Yoshikawa
      The effects of baffles, flow conditions and fluid properties on wavy motion of falling film were examined experimentally and numerically. Visualization showed that the liquid film became wavier by increasing the baffle distance and by changing liquid from water to methanol in the range of Reynolds number less than 42. Subsequently, the falling film behavior was numerically investigated by adopting VOF method. The qualitative agreements under similar flow conditions well validated both of visualization and numerical methods. The numerical results showed that a higher baffle tended to cause film break-up while the break-up was prevented by increasing the flow rates. As Reynolds number increases, the liquid film became wavier and further surface deformation became obvious. Those results demonstrated that properly-baffled reaction plate could form a noticeably wavy and deformed but quasi-stable falling film at a given flow rate for an organic solvent. The amplitude of wavy falling film on the baffled plates was correlated with Reynolds number, Bond number and non-dimensional geometrical factors, while the thickness of the wavy falling film was correlated with the non-dimensional geometrical factors. It was finally suggested that the possible enhancement of gas absorption due to the surface deformation of liquid film is of further interest targeting process intensification.
      Graphical abstract image

      PubDate: 2016-04-28T01:20:15Z
       
  • Hydrodynamic effects on three phase micro-packed bed reactor performance
           – Gold–palladium catalysed benzyl alcohol oxidation
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Noor Al-Rifai, Federico Galvanin, Moataz Morad, Enhong Cao, Stefano Cattaneo, Meenakshisundaram Sankar, Vivek Dua, Graham Hutchings, Asterios Gavriilidis
      The hydrodynamics of a three-phase micro-packed bed reactor and its effect on catalysed benzyl alcohol oxidation with pure oxygen were studied in a silicon–glass microstructured reactor. The microreactor was operated at 120°C and 1barg and contained a channel with a 300μm×600μm cross-section, packed with 1wt% Au–Pd/TiO2 catalyst, 65μm in average diameter. Improvements in the conversion of benzyl alcohol and selectivity to benzaldehyde were observed with increasing gas-to-liquid ratio, which coincided with a change in the flow pattern from a liquid-dominated slug to a gas-continuous flow regime. The observed enhancement is attributed to improved external mass transfer, associated with an increase in the gas–liquid interfacial area and reduction in the liquid film thickness that occur with gradual changes in the flow pattern. A maximum selectivity of 93% to benzaldehyde was obtained under partial wetting – which introduced the added benefit of direct gas–solid mass transfer – outperforming the selectivity in a conventional glass stirred reactor. However, this was at the expense of a reduction in the conversion. A response surface model was developed and then used to predict optimal operating conditions for maximum benzaldehyde yield, which were in the gas-continuous flow regime. This corresponded to relatively high gas flow rate in conjunction with moderate liquid flow rate, ensuring sufficient catalyst wetting with a thin film to reduce transport resistances.
      Graphical abstract image

      PubDate: 2016-04-28T01:20:15Z
       
  • Numerical modeling of anisotropic drag for a perforated plate with
           cylindrical holes
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Youngmin Bae, Young In Kim
      Direct numerical simulations of an incompressible laminar flow past a perforated plate are carried out at the pore scale. With the aim of evaluating the anisotropic drag of a perforated plate, two simple flow tests have been conducted: i) transpiration flow through a perforated plate with a regular array of cylindrical holes and ii) a linear shear flow over the plate. In the transpiration flow test, the dependence of the pressure drop on the transpiration velocity is discussed for porosities of 0.1–0.4 and hole depth to diameter ratios of 1–3 at pore-level Reynolds numbers of up to 25. The linear shear flow problem is then investigated along with a discussion of the effects of porosity, plate thickness, and pore distribution on the slip velocity at a clear fluid/perforated plate interface. Simple correlations of directional permeabilities and non-Darcy coefficients are also proposed for the perforated plate, with their application to a lid-driven cavity flow.


      PubDate: 2016-04-23T22:17:30Z
       
  • Enhancing natural product extraction and mass transfer using selective
           microwave heating
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Chai Siah Lee, Eleanor Binner, Charles Winkworth-Smith, Rebecca John, Rachel Gomes, John Robinson
      This study uses a combination of empirical observations and an analysis of mass transfer behaviour to yield new insights into the mechanism of microwave assisted extraction. Enhancements in extraction rate and yield were observed experimentally compared with conventional extraction at temperatures in excess of 50°C, however at lower temperatures there was no observable difference between the two processes. A step-change in extract yield between microwave and conventional processes was shown to be caused by selective heating. A temperature gradient of the order of 1°C is sufficient to reduce the water chemical potential within the cell structure, which changes the osmotic potential such that internal cell pressures can increase to the point where disruption occurs. This paper demonstrates the need to operate microwave extraction processes at a temperature that enables selective heating, and a newly-proposed mass transfer phenomenon that could have wider positive implications for extraction and leaching processes.
      Graphical abstract image

      PubDate: 2016-04-23T22:17:30Z
       
  • A simulation study on the conversion efficiency of catalytically active
           particulate filters
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): B. Opitz, M. Votsmeier
      A catalytically active particulate filter with a first order catalytic reaction taking place inside the filter walls is investigated by numerical simulation. The conversion efficiency for different channel geometries and operating conditions is systematically studied as a function of the governing dimensionless parameters. It is found that the conversion efficiency of a catalytically coated wall flow filter is very close to that of an ideal plug flow reactor over the full range of realistic operating conditions. Only in a range of intermediate residence times, the filter reactor shows some diffusion limitation which leads to conversion efficiencies slightly below that of the plug flow reactor. In all cases, these deviations from ideal conversion behaviour are below 15%. If the filter and the open monolith are compared at identical operating conditions and channel geometries, for fast reactions, the filter reactor shows higher conversion efficiency than the open monolith, since in this case the open monolith becomes strongly mass transfer limited. However, there can be a small range of conditions where the monolith is slightly more efficient than the filter. The reason for this effect is that due to the thinner washcoat layer the onset of mass transfer limitation in the coated monolith is shifted to higher reaction rates, compared to the filter reactor.


      PubDate: 2016-04-23T22:17:30Z
       
  • Two-fluid simulation of liquid drainage in oscillating packed beds for
           offshore floating applications
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Ion Iliuta, Faïçal Larachi
      Three-dimensional modeling of liquid drainage dynamics in vertical, inclined and oscillating packed bed reactors is virtually inexistent in the literature. An attempt was made in this work where liquid drainage dynamics in vertical, inclined and oscillating packed bed reactors was analyzed via an unsteady-state three-dimensional two-fluid hydrodynamic model. Angular oscillations of the packed bed reactor between two angled symmetrical positions and between vertical and inclined position were considered while bed non-uniformity was described using radial porosity distributions. The simulation results highlighted the fully interpretable trends of the transient liquid flow in packed beds and underlined the differences in the transient behavior of the vertical, inclined and oscillating packed bed reactors. Although the initial period of liquid drainage was dominated by gravity regardless of bed configuration, the packed bed angle with respect to gravity direction had a significant impact on the liquid drainage dynamics. Cross-sections along streamwise direction both for static and oscillating inclined positions of the bed highlighted gas-rich uppermost and liquid-rich lowermost domains. Unlike vertical beds for which drainage occurred according to a quasi-plug flow of the liquid core region, drainage of inclined beds underlined 3D liquid flow structures with liquid-rich lowermost cross-sections which accelerated liquid withdrawal. Compared to the inclined bed case, liquid drainage was delayed under oscillating regimes as a result of reverse secondary flows induced by the column motion. The initial drainage process was controlled by the liquid flow in the bed lowermost part whereas oscillations between two symmetrically angled positions led to almost cross-sectionally uniform liquid drainage distribution. This is valuable and it is plausible that at long time the performance of packed bed reactors onboard offshore floating nonstationary platforms is insignificantly affected by the oscillations between two symmetrically angled positions.


      PubDate: 2016-04-23T22:17:30Z
       
  • Analysis of di-methyl ether production routes: Process performance
           evaluations at various syngas compositions
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Minh Tri Luu, Dia Milani, Matthew Wake, Ali Abbas
      This paper investigates direct di-methyl ether (DME) production based on dry methane reforming (DMR-to-DME) and on bireforming (BiR-to-DME). Technically, DMR-to-DME is preferred to BiR-to-DME because the former produces synthesis gas (syngas) with a hydrogen to carbon monoxide molar ratio (H2/CO) of 1 which is the ideal ratio for DME synthesis. Whereas the latter produces a H2/CO close to 2 and consequently suffers from two apparent drawbacks: (1) lack of the so-called ‘synergy effect’ – a feature that enhances DME yield when operating at H2/CO close to 1, and (2) generation of a high heat capacity by-product (H2O) which makes DME recovery energy intensive. In this paper, we find that those two disadvantages actually enhance the performance of BiR compared to DMR across a range of performance metrics. Although the presence of water increases the cooling/heating duty and the distillation columns’ reboiler duty in the BiR route, more heat released from DME synthesis reactor can be utilized in the reboilers to make BiR techno-economically compatible. To assess the sustainability of DMR and BiR, evaluations are carried out against an existing industrial scale DME production route (auto-thermal-reforming (ATR)). By utilizing the carbon in the CO2 from an attached post-combustion carbon capture plant, DMR and BiR can save 22.3% methane feed uptake on average compared to the ATR process, which results in the DMR and BiR reducing CO2 emissions by at least 6.5% on average.


      PubDate: 2016-04-23T22:17:30Z
       
  • Multiphase reactive-transport simulations for estimation and robust
           optimization of the field scale production of microbially enhanced coalbed
           methane
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Gouthami Senthamaraikkannan, Ian Gates, Vinay Prasad
      The discovery that approximately 20% of natural gas is microbial in origin has elevated interest in microbially enhanced coalbed methane (MECoM). However, a rational approach to exploit this calls for the development of reservoir scale models that include the effect of microbial activity. To address this, we have developed a multiscale, multiphase, multicomponent reactive-transport model for the production of microbially enhanced coalbed methane (MECoM) that includes microbial kinetics. The model is used to evaluate field scale strategies for commercial MECoM production. Optimization studies are also conducted over a range of compositions of the injected nutrient and injector bottomhole pressures. In order to account for the effect of uncertainty in the model parameters, mean-variance robust optimization is performed, allowing a trade-off between performance and robustness. Proxy modeling is performed in a multivariate polynomial chaos expansion framework to evaluate the cost functions involved in the robust optimization and sparse expansions are constructed in order to deal with issues related to high dimensionality. The optimization strategy is tested for different trade-offs between robustness and performance. It is observed that for the given case, the location of robust optimal points does not vary unless only robustness is included in the objective function, and nominal performance is not.


      PubDate: 2016-04-23T22:17:30Z
       
  • A novel backlight fiber optical probe and image algorithms for real time
           size-shape analysis during crystallization
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Toufic El Arnaout, P.J. Cullen, Carl Sullivan
      Process analytical technology requires not only process suitable sensors, but also novel data processing approaches in order to make real time analysis feasible. In this paper, a novel in-line probe was designed, fabricated and tested for crystallization monitoring. The design benefits from state of the art optics and camera, fiber backlight illumination, and an optimized depth of focus and field of view. Image analysis steps to study both crystal size and shape are presented. These image analysis algorithms do not require manual-thresholding of individual images or time zero image subtraction, due to the use of a ‘rolling ball’ self-adapting background correction step. The approach is tolerant to blank images, noise, blurriness, out of focus objects, and common spatial or intensity variations. The method developed should help in the identification of changes in size and shape in crystal populations. Examples are presented for glass sphere standards, the crystallization of d-mannitol and l-glutamic acid, as well as an engineered needle-sphere mixture. A data binning strategy useful for future studies is also reported. The ultimate goal is control of crystallization under the Process Analytical Technology framework.


      PubDate: 2016-04-20T16:31:25Z
       
  • Inkjet printing of ceramic colloidal suspensions: Filament growth and
           breakup
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Marguerite Bienia, Martine Lejeune, Michaël Chambon, Valérie Baco-Carles, Chrystelle Dossou-Yovo, Rémi Noguera, Fabrice Rossignol
      Filament growth and breakup are investigated in the context of ceramic inkjet printing. Several inks were formulated and ejected on a printer dedicated to ceramic materials. They consisted of six colloidal inks, four simple fluids and two graphic inks. For each, stroboscopic snapshots were acquired and the filament shape was extracted and analysed, for different nozzle actuation pulses. The filament length and the thread minimum radius were measured during the ejection process. A scaling of the breakup time with the Rayleigh number was obtained, as well as a general behaviour for the filament growth rate during the ejection process.
      Graphical abstract image Highlights

      PubDate: 2016-04-20T16:31:25Z
       
  • Classical density functional theory for gas separation in nanoporous
           materials and its application to CH4/H2 separation
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Fangyuan Guo, Yu Liu, Jun Hu, Honglai Liu, Ying Hu
      Three-dimensional classical density functional theory (CDFT) has been introduced and applied to predicting gas separation in metal-organic frameworks (MOFs). The formula of CDFT is based on modified fundamental measure theory (MFMT) and mean field approximation (MFA). The accuracy of the theory has been examined by simulations, and it has been implemented into a high-throughput screening of CH4/H2 separation materials. A total of 1200 MOFs have been examined, with selectivity ranging from 70 to 220 depending on the temperature, pressure and bulk CH4/H2 ratio, which is much higher than that of real MOFs. A set of promising CH4/H2 separation MOFs has been identified. According to the analysis of the isotherm and density profile, a MOF material with a pore size that can accommodate only one CH4 molecule seems to be the best for CH4/H2 separation.


      PubDate: 2016-04-20T16:31:25Z
       
  • Advanced millireactor technology for the kinetic investigation of very
           rapid reactions: Dehydrochlorination of 1,3-dichloro-2-propanol to
           epichlorohydrin
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Cesar A. de Araujo Filho, Shuyana Heredia, Kari Eränen, Tapio Salmi
      Epichlorohydrin is an important chemical intermediate, which can be obtained by valorisation of glycerol, an inexpensive raw material obtained as a stoichiometric co-product from biodiesel production. A continuous milliscale tubular reactor was developed to conduct the synthesis of epichlorohydrin and to measure the very rapid reaction kinetics. 1,3-dichloro-2-propanol (αγ-DCP) was dehydrochlorinated with sodium hydroxide at 30–70°C. The residence times in the millireactor system were less than 25s. The kinetic data were interpreted with a plug flow model and a rate equation based on a plausible reaction mechanism. The model – the rate equation and the plug flow concept – gave a perfect description of the experimental data.


      PubDate: 2016-04-20T16:31:25Z
       
  • Hydrogen by sorption enhanced methane reforming: A grain model to study
           the behavior of bi-functional sorbent-catalyst particles
    • Abstract: Publication date: 31 July 2016
      Source:Chemical Engineering Science, Volume 149
      Author(s): Ilaria Aloisi, Nader Jand, Stefano Stendardo, Pier Ugo Foscolo
      This work utilizes a previously developed particle grain model (PGM) for carbon dioxide CaO-based sorbents, properly integrated to describe numerically the behavior of a single particle where some catalytic activity is combined to the sorption function. In this way, the model capability is extended to the investigation of a bi-functional sorbent-catalyst particle for sorption enhanced steam methane reforming (SE-SMR) processes to produce hydrogen. The kinetic description of carbon dioxide capture by calcium oxide is assumed to be that successfully validated in a previous work by means of dynamic carbonation data obtained with calcined dolomite particles of different size fluidized by a N2/CO2 gas mixture. Further simulations presented here show the ability of the sorption model to describe faithfully the additional influence of temperature, carbon dioxide concentration in the gas phase and number of solid carbonation cycles. A state of the art methane and water gas shift kinetic model is utilized to predict the particle catalytic activity in the sorption enhanced reaction process. A numerical procedure is developed in MATLAB® to integrate over time and particle radius the model equations, assuming that small particles, of the order of those of interest for fluidized bed reactors (d p =500μm), are in contact with different gas phases of constant composition. The results show that conversion of the sorbent grains and the increasing thickness of the calcium carbonate layer around them make carbon dioxide sorption and methane reforming rate strong functions of residence time of particle in the reacting atmosphere, with different scenarios for the interaction between catalytic steam reforming and CO2 sorption. The model predicts that, with sufficient amount of calcium oxide inside the particle, conditions exist where the time averaged rates of carbon dioxide sorption, methane reforming and water gas shift, respectively, are such that a perfect balance exists between carbon dioxide captured by the solid phase and CO+CO2 produced by the reforming reactions.


      PubDate: 2016-04-20T16:31:25Z
       
 
 
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